title: Prevalence of incidental narrowing of the superior segment of the internal jugular vein in patients without multiple sclerosis.
abstract: OBJECTIVE
  Internal jugular vein (IJV) narrowing superiorly is likely relatively frequent. IJV narrowing has been proposed as a potential pathophysiologic component for multiple sclerosis (MS). Our purpose was to investigate the prevalence of incidental superior IJV narrowing in patients imaged with neck computed tomography angiography (CTA) for reasons unrelated to IJV pathology or MS.
  
  
  METHODS
  We retrospectively identified 164 consecutive adult patients who had undergone neck CTA in which at least one IJV superior segment was opacified (158 right, 155 left IJVs). At the narrowest point of the upper IJV, each IJV was assessed for dominance, graded (shape and narrowing), measured (diameter and area), and located (axially and craniocaudally). Associations were analyzed using Spearman rank correlations (p < 0.05 significant). Medical records were reviewed for MS.
  
  
  RESULTS
  Among 164 patients, at least one IJV was: absent/pinpoint in 15 % (25/164), occluded/nearly occluded in 26 % (43/164). Shape, narrowing, and the three measurements all correlated with each other (all p < 0.01). Lateral location with respect to C1 transverse foramen correlated with subjectively and objectively smaller IJVs (p < 0.01). The most common craniocaudal location was at the C1 transverse process (79 % (125/158) of right and 81 % (126/155) of left IJVs). No patient had a diagnosis of MS.
  
  
  CONCLUSIONS
  The appearance of the superior IJV is variable, with an occlusive/near-occlusive appearance present in approximately one-quarter of patients without known MS undergoing CTA. Radiologists should be aware of and cautious to report or ascribe clinical significance to this frequent anatomic variant.
authors.affiliation: Division of Neuroradiology, Department of Radiology, Mayo Clinic, 200 1st St SW, Rochester, 55905, MN, USA.
authors.forename: F E
authors.initials: FE
authors.lastname: Diehn
authors.forename: K M
authors.initials: KM
authors.lastname: Schwartz
authors.forename: C H
authors.initials: CH
authors.lastname: Hunt
authors.forename: L J
authors.initials: LJ
authors.lastname: Eckel
authors.forename: N G
authors.initials: NG
authors.lastname: Campeau
authors.forename: R E
authors.initials: RE
authors.lastname: Carter
authors.forename: J B
authors.initials: JB
authors.lastname: Allred
authors.forename: D F
authors.initials: DF
authors.lastname: Kallmes
mesh_terms: D015984:Causality; D015897:Comorbidity; D005260:Female; D006801:Humans; D033162:Incidental Findings; D007601:Jugular Veins / Q000002:abnormalities / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000453:epidemiology; D010690:Phlebography / Q000706:statistics & numerical data; D015995:Prevalence; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data; D020246:Venous Thrombosis / Q000000981:diagnostic imaging* / Q000453:epidemiology*